This invention relates to steam turbines and more particularly to a nozzle chamber system therefor. Previously nozzle chambers were made as an integral part of the inner cylinder being welded at the inlet end to a flexible neck on the inlet cylinder. For each arc of admission there was an individual chamber segment cantilevered from the inlet barrel weld joint. The cantilevered portion was otherwise constrained only in the turbine axial direction by tongue and groove fits. There was no additional constraint in the other directions. In these turbines the inlet sleeve was installed in a bore in the nozzle chamber barrel where sealing was accomplished by a bell seal as shown in U.S. Pat. No. 3,907,308. For reasons not fully understood the nozzle chambers and inlet sleeve have experienced significant vibration excitation. It has been postulated that inadequate constraint of the nozzle chamber has contributed to excessive wear in the tonque and groove fits allowing increasingly larger vibrational amplitudes sometimes resulting in high cycle fatigue cracking at the weld neck. There is also some reason to believe that the mating of the inlet sleeve into the nozzle chamber barrel may have caused vibratory interaction which could have contributed to the fatigue of the inlet sleeve on the nozzle chamber neck. Other manufacturers have used two nozzle chambers as disclosed herein, but the upper and lower halves were normally bolted or pinned at the horizontal joint.